Post-hoc analyses of the edaravone clinical trials Study 16 and Study 19: a step toward more efficient clinical trial designs in amyotrophic lateral sclerosis

The sense of antisense therapies in ALS

Treatment of patients with amyotrophic lateral sclerosis (ALS) has entered a new era now that encouraging results about antisense oligonucleotides (ASOs) are becoming available and a first ASO therapy for ALS has been approved by the FDA. Moreover, there is hope not only that ALS can be stopped but also that symptoms can be reversed. Until now, degrading ASOs seemed to be successful mostly for rarer forms of familial ALS. However, the first attempts to correct mis-splicing events in sporadic ALS are underway, as well as a clinical trial examining interference with a genetic modifier. In this review, we discuss the current status of using ASOs in ALS and the possibilities and pitfalls of this therapeutic strategy.

Green synthesis of zinc and nickel dual-doped cerium oxide nanoparticles: antioxidant activity and cytotoxicity effects

Cerium oxide nanoparticles (CeO2-NPs) and Zn-Ni dual-doped CeO2-NPs were synthesized through a green approach by the implication of zucchini peel (Cucurbita pepo) extract as a capping and reduction agent. All the synthesized samples were studied by the results of FTIR, UV-Vis, XRD, and FESEM/EDAX/PSA analyses. The Zn-Ni dual-doped CeO2-NPs contained a spherical morphology and their size was observed to increase at higher temperatures. The conducted MTT assay on the Huh-7 cell line displayed 50% of cells annihilation as a result of using undoped CeO2-NPs and Zn-Ni dual-doped CeO2-NPs at the inhibitory concentrations (IC50) of 700 and 185.4 μg/mL, respectively. We also evaluated the enzymatic functionality of SOD and CAT of undoped CeO2-NPs and dual-doped NPs and found it to be dose dependent. Moreover, Zn-Ni dual-doped CeO2-NPs intensified the CAT activity without causing any changes in SOD activity in similar concentrations.

Predicting Ambulatory Capacity in Parkinson's Disease to Analyze Progression, Biomarkers, and Trial Design

BACKGROUND

In Parkinson's disease (PD), gait and balance is impaired, relatively resistant to available treatment and associated with falls and disability. Predictive models of ambulatory progression could enhance understanding of gait/balance disturbances and aid in trial design.

OBJECTIVES

To predict trajectories of ambulatory abilities from baseline clinical data in early PD, relate trajectories to clinical milestones, compare biomarkers, and evaluate trajectories for enrichment of clinical trials.

METHODS

Data from two multicenter, longitudinal, observational studies were used for model training (Tracking Parkinson's, n = 1598) and external testing (Parkinson's Progression Markers Initiative, n = 407). Models were trained and validated to predict individuals as having a "Progressive" or "Stable" trajectory based on changes of ambulatory capacity scores from the Movement Disorders Society Unified Parkinson's Disease Rating Scale parts II and III. Survival analyses compared time-to-clinical milestones and trial outcomes between predicted trajectories.

RESULTS

On external evaluation, a support vector machine model predicted Progressive trajectories using baseline clinical data with an accuracy, weighted-F1 (proportionally weighted harmonic mean of precision and sensitivity), and sensitivity/specificity of 0.735, 0.799, and 0.688/0.739, respectively. Over 4 years, the predicted Progressive trajectory was more likely to experience impaired balance, loss of independence, impaired function and cognition. Baseline dopamine transporter imaging and select biomarkers of neurodegeneration were significantly different between predicted trajectory groups. For an 18-month, randomized (1:1) clinical trial, sample size savings up to 30% were possible when enrollment was enriched for the Progressive trajectory versus no enrichment.

CONCLUSIONS

It is possible to predict ambulatory abilities from clinical data that are associated with meaningful outcomes in people with early PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Oral Edaravone - Introducing a Flexible Treatment Option for Amyotrophic Lateral Sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a progressive and incurable neurodegenerative disease. While pharmacotherapy options remain limited, the Food and Drug Administration (FDA) approved intravenous (IV) and oral edaravone for the treatment of ALS in 2017 and 2022, respectively. With the addition of oral edaravone, patients with ALS may exclusively use oral medications.

AREAS COVERED

The authors performed a review of the published literature using the United States (US) National Library of Medicine's PubMed.gov resource to describe the pharmacokinetics, pharmacodynamics, safety, and efficacy of oral edaravone, as well as pertinent completed and ongoing clinical trials, including the oral edaravone clinical trial development program. The clinical profile of oral edaravone is also discussed.

EXPERT OPINION

Edaravone has been shown to slow the rate of motor function deterioration experienced by patients with ALS. As the oral formulation has been approved, patients with ALS may use it alone or in combination with other approved therapeutics. Additional clinical trials and real-world evidence are ongoing to gain further understanding of the clinical profile of oral edaravone.

Characterising ALS disease progression according to El Escorial and Gold Coast criteria

BACKGROUND

The Gold Coast criteria (GCC) have been proposed as a means of selecting patients for amyotrophic lateral sclerosis (ALS) clinical trials. We aimed to characterise disease progression according to the GCC.

METHODS

Data from population-based ALS registries from the Netherlands and Belgium were analysed. The GCC additionally define ALS as lower motor neuron (LMN) dysfunction in ≥2 body regions without upper motor neuron dysfunction. Therefore, the revised El Escorial criteria (rEEC) were supplemented with a 'Gold Coast ALS' category for patients with only LMN dysfunction in ≥2 body regions. We assessed survival time, ALS Functional Rating Scale (ALSFRS-R) progression rates and between-patient variability per diagnostic category.

RESULTS

We included 5957 ALS patients, of whom 600 (10.1%) fulfilled the GCC but not the rEEC, and 95 (1.6%) fulfilled only the rEEC. ALSFRS-R progression rates were similar for the rEEC (0.84 points/month) and GCC (0.81 points/month) with similar variability (standard deviation of 0.59 vs. 0.60) and median survival time (17.8 vs.18.7 months). Survival time and average progression rates varied (p<0.001) between categories. Per category, however, there was considerable between-patient variability with progression rates ranging from: -2.10 to -0.14 (definite), -1.94 to -0.06 (probable), -2.10 to -0.02 (probable laboratory supported), -1.79 to -0.02 (possible) and -1.31 to 0.08 (Gold Coast).

CONCLUSIONS

The GCC broaden the definition of ALS, allowing more patients to participate in trials, while minimally impacting population heterogeneity. Given the large variability per diagnostic category, selecting only specific categories for trials may not result in a more homogeneous study population.

Edaravone efficacy in amyotrophic lateral sclerosis with reduced forced vital capacity: Post-hoc analysis of Study 19 (MCI186-19) [clinical trial NCT01492686]

Background

Edaravone slowed the rate of functional decline in subjects with amyotrophic lateral sclerosis (ALS) in phase 3 study MCI186-19 (Study 19). One of the Study 19 inclusion criteria was forced vital capacity (FVC) ≥80% of predicted (≥80%p). Therefore, the study provided no information on edaravone efficacy in subjects with FVC <80%p. In Study 19, 24-week, double-blind treatment was followed by open-label treatment where all subjects received edaravone. At 24 weeks, some subjects had FVC <80%p (FVC₂₄ <80%p). This allowed for post-hoc assessment of the effects of edaravone in subgroups of subjects with FVC₂₄ ≥80%p vs <80%p.

Objective

To address the question of the efficacy of edaravone in ALS patients with FVC <80%p.

Methods

Post-hoc analysis of Study 19 comparing edaravone efficacy at week 48 in subjects with FVC₂₄ ≥80%p vs <80%p.

Results

With edaravone treatment, subjects in both the FVC₂₄ ≥80%p and the FVC₂₄ <80%p subgroups experienced a reduction in ALS Functional Rating Scale-Revised (ALSFRS-R) score loss vs placebo subjects through week 48. For the FVC₂₄ ≥80%p subgroup, the changes in ALSFRS-R scores from baseline to week 48 were −7.63 for edaravone-edaravone vs −9.69 for placebo-edaravone, a difference of 2.05 (P = .034; 95% CI: 0.16, 3.94). For the FVC₂₄ <80%p subgroup, the changes in ALSFRS-R scores from baseline to week 48 were −10.26 for edaravone-edaravone vs −15.20 for placebo-edaravone, a difference of 4.94 (P = .0038; 95% CI: 1.64, 8.25). Linear regression analysis indicated that, in the FVC₂₄ <80%p subgroup, there was a notable change in the slope of the ALSFRS-R score-vs-time graph after the start of edaravone treatment.

Conclusion

ALS subjects in the Study 19 placebo arm had a slowing in disease progression, even when edaravone was added with an FVC of <80%p prior to starting edaravone. A randomized, placebo-controlled study is needed to validate these post-hoc findings.

Evaluation of clinical outcome and safety profile of edaravone in treatment of amyotrophic lateral sclerosis: a 72-week single-center experience

Edaravone is a free radical scavenger that has been recently approved for treatment of Amyotrophic lateral sclerosis (ALS) to delay functional decline. We aim to evaluate edaravone efficacy and safety in ALS patients in the main neurology tertiary center in Kuwait over 72-week period. We conducted a prospective observational cohort study in the main tertiary hospital over 72-week period from July 2018 until January 2020. Patients were assessed at baseline, 24, 48 and 72 weeks of therapy using ALSFRS-R score, MRC sum score, FVC value, among other parameters. Seventeen consecutive patients were evaluated. All patients were assessed at baseline, 24 and 48 weeks, while 9 patients (52.9%) were further assessed at 72 weeks. There was a statistically significant decline of ALSFRS-R at 72 weeks, MRC sum score at 48 and 72 weeks, while the decline in FVC was not statistically significant. Glycosuria was found in only one patient. Our study showed significant functional decline after 1 year of edaravone therapy with preserved respiratory function. The drug had a high level of dissatisfaction among our cohort despite having a high safety profile.

Evidence for generalizability of edaravone efficacy using a novel machine learning risk-based subgroup analysis tool

Introduction: The edaravone development program for amyotrophic lateral sclerosis (ALS) included trials MCI186-16 (Study 16) and MCI186-19 (Study 19). A cohort enrichment strategy was based on a Study 16 post hoc analysis and applied to Study 19 to elucidate a treatment effect in that study. To determine whether the Study 19 results could be generalized to a broader ALS population, we used a machine learning (ML) model to create a novel risk-based subgroup analysis tool. Methods: A validated ML model was used to rank order all Study 16 participants by predicted time to 50% expected vital capacity. Subjects were stratified into nearest-neighbor risk-based subgroups that were systematically expanded to include the entire Study 16 population. For each subgroup, a statistical analysis generated heat maps that revealed statistically significant effect sizes. Results: A broad region of the Study 16 heat map with significant effect sizes was identified, including up to 70% of the trial population. Incorporating participants identified in the cohort enrichment strategy yielded a broad group comprising 76% of the original participants with a statistically significant treatment effect. This broad group spanned the full range of the functional score progression observed in Study 16. Conclusions: This analysis, applying predictions derived using an ML model to a novel methodology for subgroup identification, ascertained a statistically significant edaravone treatment effect in a cohort of participants with broader disease characteristics than the Study 19 inclusion criteria. This novel methodology may assist clinical interpretation of study results and potentially inform efficient future clinical trial design strategies.

Current trends in the clinical trial landscape for amyotrophic lateral sclerosis

PURPOSE OF REVIEW

To review the current developments in the design and conduct of clinical trials for amyotrophic lateral sclerosis (ALS), illustrated by a critical appraisal of ClinicalTrials.gov.

RECENT FINDINGS

In total, 63 clinical trials were included in the analysis, of which 13 phase 1, 35 phase 2 and 15 phase 3. Virtually all phase 3 clinical trials can be classified as randomized, placebo controlled, whereas this is only true for 57% of the phase 2 clinical trials. There are promising developments in the routes of drug administration, eligibility criteria, efficacy endpoints and overall trial design. Some of these innovative approaches may, however, not fulfil clinical trial guidelines or regulatory requirements. This could delay the development of effective therapy or hamper our ability to determine whether a treatment is truly (in)effective. The initiation of trial consortia comprising patient organizations, academia, industry and funding bodies may significantly strengthen the future clinical trial landscape for ALS.

SUMMARY

The ALS clinical trial landscape is currently highly active with several promising innovative developments and therapeutic options. By further refinement of evidence-based guidelines, and alignment of our current endeavours, we may soon be able to positively impact the lives of people living with ALS.

Tetramethylpyrazine nitrone improves motor dysfunction and pathological manifestations by activating the PGC-1α/Nrf2/HO-1 pathway in ALS mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive loss of upper and lower motor neurons that results in skeletal muscle atrophy, weakness and paralysis. Oxidative stress plays a key role in the pathogenesis of ALS, including familial forms of the disease arising from mutation of the gene coding for superoxide dismutase (SOD1). We have used the SOD1^G93A ALS mouse model to investigate the efficacy of 2-[[(1,1-dimethylethyl)oxidoimino]-methyl]-3,5,6-trimethylpyrazine (TBN), a novel tetramethylpyrazine derivative armed with a powerful free-radical scavenging nitrone moiety. TBN was administered to mice by intraperitoneal or intragastric injection after the onset of motor deficits. TBN slowed the progression of motor neuron disease as evidenced by improved motor performance, reduced spinal motor neuron loss and the associated glial response, and decreased skeletal muscle fiber denervation and fibrosis. TBN treatment activated mitochondrial antioxidant activity through the PGC-1α/Nrf2/HO-1 pathway and decreased the expression of human SOD1. These findings suggest that TBN holds promise as a therapeutic agent for ALS.

Longitudinal multi-modal muscle-based biomarker assessment in motor neuron disease

Background

Clinical phenotypic heterogeneity represents a major barrier to trials in motor neuron disease (MND) and objective surrogate outcome measures are required, especially for slowly progressive patients. We assessed responsiveness of clinical, electrophysiological and radiological muscle-based assessments to detect MND-related progression.

Materials and methods

A prospective, longitudinal cohort study of 29 MND patients and 22 healthy controls was performed. Clinical measures, electrophysiological motor unit number index/size (MUNIX/MUSIX) and relative T2- and diffusion-weighted whole-body muscle magnetic resonance (MR) were assessed three times over 12 months. Multi-variable regression models assessed between-group differences, clinico-electrophysiological associations, and longitudinal changes. Standardized response means (SRMs) assessed sensitivity to change over 12 months.

Results

MND patients exhibited 18% higher whole-body mean muscle relative T2-signal than controls (95% CI 7–29%, p < 0.01), maximal in leg muscles (left tibialis anterior 71% (95% CI 33–122%, p < 0.01). Clinical and electrophysiological associations were evident. By 12 months, 16 patients had died or could not continue. In the remainder, relative T2-signal increased over 12 months by 14–29% in right tibialis anterior, right quadriceps, bilateral hamstrings and gastrocnemius/soleus (p < 0.01), independent of onset-site, and paralleled progressive weakness and electrophysiological loss of motor units. Highest clinical, electrophysiological and radiological SRMs were found for revised ALS-functional rating scale scores (1.22), tibialis anterior MUNIX (1.59), and relative T2-weighted leg muscle MR (right hamstrings: 0.98), respectively. Diffusion MR detected minimal changes.

Conclusion

MUNIX and relative T2-weighted MR represent objective surrogate markers of progressive denervation in MND. Radiological changes were maximal in leg muscles, irrespective of clinical onset-site.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09580-x) contains supplementary material, which is available to authorized users.

Antioxidant Enzyme-Mimetic Activity and Neuroprotective Effects of Cerium Oxide Nanoparticles Stabilized with Various Ratios of Citric Acid and EDTA

Cerium oxide (CeO2) nanoparticles (CeNPs) are potent antioxidants that are being explored as potential therapies for diseases in which oxidative stress plays an important pathological role. However, both beneficial and toxic effects of CeNPs have been reported, and the method of synthesis as well as physico-chemical, biological, and environmental factors can impact the ultimate biological effects of CeNPs. In the present study, we explored the effect of different ratios of citric acid (CA) and EDTA (CA/EDTA), which are used as stabilizers during synthesis of CeNPs, on the antioxidant enzyme-mimetic and biological activity of the CeNPs. We separated the CeNPs into supernatant and pellet fractions and used commercially available enzymatic assays to measure the catalase-, superoxide dismutase (SOD)-, and oxidase-mimetic activity of each fraction. We tested the effects of these CeNPs in a mouse hippocampal brain slice model of ischemia to induce oxidative stress where the fluorescence indicator SYTOX green was used to assess cell death. Our results demonstrate that CeNPs stabilized with various ratios of CA/EDTA display different enzyme-mimetic activities. CeNPs with intermediate CA/EDTA stabilization ratios demonstrated greater neuroprotection in ischemic mouse brain slices, and the neuroprotective activity resides in the pellet fraction of the CeNPs. The neuroprotective effects of CeNPs stabilized with equal proportions of CA/EDTA (50/50) were also demonstrated in two other models of ischemia/reperfusion in mice and rats. Thus, CeNPs merit further development as a neuroprotective therapy for use in diseases associated with oxidative stress in the nervous system.

ALS blood expression profiling identifies new biomarkers, patient subgroups, and evidence for neutrophilia and hypoxia

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a debilitating disease with few treatment options. Progress towards new therapies requires validated disease biomarkers, but there is no consensus on which fluid-based measures are most informative.

METHODS

This study analyzed microarray data derived from blood samples of patients with ALS (n = 396), ALS mimic diseases (n = 75), and healthy controls (n = 645). Goals were to provide in-depth analysis of differentially expressed genes (DEGs), characterize patient-to-patient heterogeneity, and identify candidate biomarkers.

RESULTS

We identified 752 ALS-increased and 764 ALS-decreased DEGs (FDR < 0.10 with > 10% expression change). Gene expression shifts in ALS blood broadly resembled acute high altitude stress responses. ALS-increased DEGs had high exosome expression, were neutrophil-specific, associated with translation, and overlapped significantly with genes near ALS susceptibility loci (e.g., IFRD1, TBK1, CREB5). ALS-decreased DEGs, in contrast, had low exosome expression, were erythroid lineage-specific, and associated with anemia and blood disorders. Genes encoding neurofilament proteins (NEFH, NEFL) had poor diagnostic accuracy (50-53%). However, support vector machines distinguished ALS patients from ALS mimics and controls with 87% accuracy (sensitivity: 86%, specificity: 87%). Expression profiles were heterogeneous among patients and we identified two subgroups: (i) patients with higher expression of IL6R and myeloid lineage-specific genes and (ii) patients with higher expression of IL23A and lymphoid-specific genes. The gene encoding copper chaperone for superoxide dismutase (CCS) was most strongly associated with survival (HR = 0.77; P = 1.84e-05) and other survival-associated genes were linked to mitochondrial respiration. We identify a 61 gene signature that significantly improves survival prediction when added to Cox proportional hazard models with baseline clinical data (i.e., age at onset, site of onset and sex). Predicted median survival differed 2-fold between patients with favorable and risk-associated gene expression signatures.

CONCLUSIONS

Peripheral blood analysis informs our understanding of ALS disease mechanisms and genetic association signals. Our findings are consistent with low-grade neutrophilia and hypoxia as ALS phenotypes, with heterogeneity among patients partly driven by differences in myeloid and lymphoid cell abundance. Biomarkers identified in this study require further validation but may provide new tools for research and clinical practice.